The issues of security and ease of use of a computing platform are often in conflict. For commercial applications, a client computing platform typically operates in an environment where its behaviour is vulnerable to modification. Such modification can be made by local or remote entities. This has given rise to concerns, especially in the field of e-commerce, that transactions conducted on a computer might be subject to some form of misdemeanour, such as theft of credit card details. These perceived insecurities may limit the willingness of users to undertake e-commerce transactions on either local or remote computer systems.
The data processing environment (or environment) of a computer platform or other data processing appliance consists of the other computing entities (computer platforms or any other data processing appliance) that are discrete from the computer platform and are in communication with it through one or more data networks. For a computer entity to form part of the environment of a computer platform, the computer platform must be able to interact with the entity but must not be constrained to do so—at some level, interaction must be voluntary. The boundary of an environment will generally be considered in terms of network connections (or other network “distance”) between one point and another—for some purposes, the data processing environment of a computer platform may be considered its local network and no more, whereas for other purposes, the data processing environment of a computer platform may extend much further (for example, across a company intranet). There are existing security applications, such as virus checkers and fire walls which can be installed in computer systems in order to limit their vulnerability to viruses or to malicious users seeking to take control of the machine remotely. However, these security applications execute on computing platforms under the assumption that the platform is operating as intended and that the platform itself will not subvert the processes used by these applications.
Users engaging in communication with a remote or unfamiliar data processing environment may nevertheless be concerned about the security of that environment as a whole rather than just the security of the computing device with which they have made initial contact. Thus users seek reassurance that the computing environment can be trusted.
As used herein, the word “trust” is used to mean that something can be trusted, in the sense that it is working in the way that it is intended and expected to work and is not or has not been tampered with in order to run malicious operations.